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Technical guidance on herbicide use in soybean and corn belt compound planting in 2023

Release time: 2023-03-29

      Soybean and corn belt combined planting is an innovative development of traditional interplanting technology, which puts forward higher requirements for herbicide variety selection, application time and application method。In order to scientifically regulate the application of weeding technology in soybean and corn belt composite planting and improve the control effect, this scheme is formulated for reference everywhere。

      First, prevention and control strategies

      The principle of comprehensive control should be adhered to for weed control in soybean and corn belt composite planting, and the effects of agricultural physical measures such as tilling and rotating tillage and mulching should be brought into full play to reduce the occurrence base of weeds in the field and reduce the pressure of chemical weed control。The application strategy of herbicide should be "soil closure treatment before seeding, orientation of stems and leaves after seeding, or isolation spray treatment as a supplement",According to the characteristics of different regions, different planting patterns,It is necessary to consider the safety of soybean and corn growth when stubble,It is also necessary to consider the safety of the next crop and the next year's soybean and corn belt compound planting rotation,Scientific and rational selection of herbicide varieties and application methods。

      Adapt to local conditions。All localities should formulate weed control technical plans according to the planting period, planting mode, weed species, etc., scientifically select appropriate herbicide varieties and dosages according to local conditions, and carry out accurate classification guidance。

      Treat the early and the young。Priority should be given to soil closure treatment after seeding and before seeding to reduce the pressure of weeding after seeding。Post-seedling weeding focuses on the emergence and seedling stage, which is the key stage of weed control and the weeding effect is good。

      Safe and efficient。Herbicide varieties used for weed control should ensure high efficiency, low risk, safe growth of the current crop of soybeans, corn and surrounding crops, while not affecting the next crop。

      2. Technical measures

      (1) Soybean and corn belt intercropping 

      In southwest China, there are abundant rainfall and many kinds of weeds, which is difficult to control。Corn is sown before soybean, herbicide use should be "blocked in combination"。After seeding and before seeding, the corn was treated with the soil sealing treatment of sperimetolachlor (or acetochlor) + thiophensulfuron,If weeds are already present in the field before corn sowing;The soil sealing effect is not ideal and requires spray treatment of stems and leaves,Nicosulfuron + clofluropyloxyacetic acid (or dichloropyridinic acid, or methazon) can be used in the maize planting area at 3 to 5 leaf stage。

      Three days before soybean sowing, phosphine oxalammonium was used for directional spraying in field。After seeding and before seeding, the soil was closed by using imetolachlor (or acetochlor) + thiophensulfuron and other agents。If the soil sealing effect is not ideal and the stem and leaf spray treatment is required, in the 3 to 4 soybean three leaf compound stage, the use of bioquinoline (or high efficiency fluropyrazoline, biopiriflopyrazoline, endroxone) + carboxyflurane (or Methanoxon) directed (soybean planting area) stem and leaf spray。

      (2) Soybean and corn belt intercropping 

      In Huang-Huai-hai, middle and lower reaches of Yangtze River and northwest China, soybean and corn were sown at the same time, and the application of herbicide was mainly based on soil sealing treatment before seeding, which was required to be completed within 2 days after seeding。The soil was sealed by using imetolachlor (or imetolachlor, etachlor) + zomesulfuron (or thiophensulfuron)。When the soil is closed with herbicide in the previous wheat field,Before planting, it is best to carry out rotary tillage to eliminate stubble and create moisture,Then sow and apply medicine;Field of live wheat stubble,Need to increase the water consumption of mu,If possible, water in time after application;In the northwest and other arid, wind-blown areas,It is best to mix the soil after herbicide application,Water where possible。

      When the soil sealing effect is not ideal and the stem and leaf spray treatment is required,It can be in 3 ~ 5 leaf stage after maize seedling,2 to 3 pieces of soybean three compound leaf stage,Weed 2 ~ 5 leaf stage,According to local grass conditions,Use nimosulfuron (or benzoxalone) + Metosol (or clofluropyloxyacetic acid) for corn, and use bioquinoline (or high-efficiency fluropyramine) + Metosol (or ethoxyflurane) for stalk and leaf directional spraying for soybean weeding (use a physical curtain to separate corn and soybeans).。In the later stage, the weeds that are difficult to control can be pulled manually。

      Huang-huai-hai area: most of the fields were sown with no-tillage and stubble, and there were many weeds in the fields after wheat harvest. Before corn and soybeans were sown, the weeds that had emerged were sprayed with phosphine oxalate。Soil closure treatment is applied immediately after sowing corn and soybeans,Soil surface wet plots need not less than 60 liters of water per mu,The amount of water per mu of dry land should be increased to 80-90 liters.Or soil closed after treatment,Can be combined with sprinkler irrigation, rainfall or irrigation measures,The chemical agent attached to the wheat straw is leached to the soil surface,Improve sealing effect。

      In Northwest China, black mulching technology was popularized to reduce the occurrence base of weeds in the field。In the field without film cover, the soil was closed before seeding。

      Inner Mongolia: Use full film mulching or half film mulching to control some weeds。In the field without film cover, soil sealing treatment was carried out before seeding, combined with directional spraying of special herbicides for corn and soybean after seeding。

      Third, precautions

      (1) Priority should be given to seven herbicides registered on corn and soybean at the same time, such as spermetolachlor, isometolachlor, etachlor, dimethylpentalin, Zomethansulfuron, thiophensulfuron and Methanoxon。According to the results of the soybean and corn compound planting herbicide test in 2022, the soil sealing treatment of sulfonpyrazole + azinone, imetolachlor + propylflumlor and other agents has good herbicidal effect, and can be selected according to the product registration situation。

      (2) In the selection of stem and leaf treatment herbicides, pay attention to the selection of herbicide varieties with high safety for adjacent crops and next crops, and strictly control the dosage。It is easy to cause damage to maize by the floating of the agents, such as genquequinoline, high-efficiency fluopyriphenoline, genpirofenoline and enoxalone.Chlorofluropyloxyacetic acid and dichloropyridinic acid were easily harmful to soybean, while atrazine and nimosulfuron were easily harmful to soybean, wheat and rape。

      (3) If herbicide damage occurs, indolebutyric acid, brassinolactone, gibberellic acid, potassium dihydrogen phosphate, etc. can be sprayed on the crop leaf surface in time, which can alleviate the drug damage to a certain extent。At the same time, we should strengthen the management of water and fertilizer, promote the roots and seedlings, enhance the resistance to stress, and promote the rapid recovery of crops。

      (4) When using a spray rod sprayer for directional spraying, a protective cover should be installed to prevent the herbicide from drifting to nearby crops, and it should be noted that the herbicide does not run off to nearby crops。Spray equipment should be thoroughly cleaned before use, to prevent the residual chemicals to cause crop damage。

      (5) When spraying herbicides, pay attention to weather changes such as wind, wind direction and rain。Use the medicine when there is no wind and the minimum temperature is not less than 4℃, and the best time to use the medicine is before 10 am and after 4 PM。It is not suitable to spray when the temperature exceeds 28 ° C and the wind speed exceeds 2 m/s, and there should be no rain within 12 hours after application of the stem and leaf spray to prevent the drug effect from decreasing and the droplet drifting。

      (Source: National Agricultural Technology Extension Network